1. Technical Field
The present invention relates to a technology which detects the presence or absence of liquid in a liquid container which supplies liquid to a liquid consuming apparatus.
2. Related Art
As an example of a liquid consuming apparatus, a so-called ink jet printer is known which prints images or the like by ejecting liquid, such as ink, from an ejection head. The liquid which is ejected from the ejection head is received in a dedicated liquid container such as liquid cartridge or the like, and is supplied to the ejection head through a connecting tube or the like. In addition, in general, when the liquid in a liquid cartridge runs out, each cartridge is replaced with a new cartridge.
In such a liquid consuming apparatus, there is a concern that the ejection head may be damaged when the liquid in the liquid cartridge runs out, and an ejection operation is performed in a state where the liquid is not supplied to the ejection head. Accordingly, a cartridge is proposed (JP-A-2007-307894) in which a detection system is mounted which detects that the liquid in the liquid cartridge has run out. Since the detection system is installed in the liquid cartridge itself, it is possible to rapidly detect that the liquid in the cartridge has run out.
In addition, various systems which detect the depletion of the liquid have been proposed. For example, a detection system has been proposed (JP-A-2007-136807) which detects a state where ink in a sub-tank is running out in the sub-tank which is installed in a carriage along with an ejection head, and to which ink is supplied through a tube from a main tank which is provided in a place where there is no movement other than the carriage. In the sub-tank, an opening portion of a case which has the opening portion on a wall surface is blocked by a deformable member which is flexible, and the deformable member is urged to the outside in a pressing manner by a compression spring from the inside of the case. In addition, a plate-like member (lever) is urged to the deformable member so as to come in contact with the deformable member, and the plate-like member (lever) rotates, following the deformable member which is drawn to the inside of the sub-tank due to a negative pressure in the sub-tank which is caused due to consumption of the ink. When a free end side of the plate-like member (lever) is detected along with the rotation using an optical sensor, it is determined that the ink in the sub-tank has run out, then a supply pump is operated to replenish ink to the sub-tank (JP-A-2007-136807).
Meanwhile, there was a problem in that when the detection system proposed in JP-A-2007-307894 is assumed to be installed in the liquid cartridge itself, the cost of the cartridge increases, since the expensive sensor is also replaced whenever the cartridge is replaced.
In addition, in a detection system which is proposed in JP-A-2007-136807, since the lever was directly detected using the sensor, there is a concern that the sensor is also contaminated when the lever which comes in contact with a diaphragm in the liquid chamber has liquid, such as ink, which is leaked attached thereto, and as a result, there is a concern that the accuracy of detecting that liquid has run out may deteriorate.